Lignite
Three reasons speak for German lignite: economic efficiency, environmental compatibility and security of supplies. In the base load range, it makes a crucial contribution toward maintaining a secure and low-cost energy supply in Germany as a subsidy-free and domestic source of energy.
Our lignite deposits will be available for generations to come. We extract just less than 100 million tons of lignite per year, a quantity ensured until the middle of this century by existing approvals for opencast mines based on deposits of up to 4 billion tons. These facts make it clear that lignite plays a key role in the energy mix of RWE Power.
Since our lignite is located just under the surface, it is mined in opencast operations. In the opencast mines of Garzweiler, Hambach and Inden, gigantic bucket wheel excavators dig the brown gold out of the earth. These excavators are the hallmark of the state-of-the-art mining technology used by RWE Power: standing 90 meters tall and 200 meters long and weighing some 13,000 tons, they are some of the world’s largest mobile machines.
Opencast mines always involve an interference with nature and habitats. Therefore, extraction and the subsequent recultivation of the depleted mining areas are two corporate goals of equal priority. This yields ecologically high-quality landscapes with lively flora and fauna. For the people who have to give way to the advancing opencast lignite mines, joint and socially compatible resettlement schemes have proved their worth down many decades.
Around 10 per cent of the coal we mine is upgraded to produce solid fuels, such as briquettes, pulverized lignite and coke, or fluidized bed lignite for industry and households. Some 90 per cent of the lignite goes into power generation. Our four power plant sites – Weisweiler, Niederaußem, Neurath and Frimmersdorf – with a combined installed capacity of some 10,000 MW secure 15 per cent of Germany’s electricity demand. Approx. 29 per cent of the country's power generation is based on lignite.
Lignite-based power generation places heavy demands on the efficiency of power plants, particularly where climate protection is concerned. The finest example of their technical performance is our lignite-fired power plant with optimized plant engineering (BoA) at Niederaußem. With over 43 per cent efficiency, this unit is setting standards worldwide. Compared with legacy systems, it can reduce CO2 emissions by up to 3 million tons per year.
Furthermore, we are bundling our research projects for lowering and converting CO2 in this plant and its technology. Research and development projects are an important component in our CO2 climate-protection strategy, and these activities have turned Niederaussem into a "Coal Innovation Centre". Here, we are gaining invaluable insights that can be ported to other plants. This is also where RWE Power wishes to cultivate an increased exchange with international experts.
At Grevenbroich-Neurath, RWE is building another lignite-fired power station with optimized plant engineering; commercial operation is set to start in 2010. This is our proactive contribution toward sparing the environment and promoting worldwide climate protection.
In 2006/2007, RWE started the commercial operation of two topping gas turbines at the 600-MW units G and H in the Weisweiler power plant. They have a net capacity of 190 megawatts and are switched before the lignite-fired units. The turbines help raise energy efficiency in lignite-based generation at the existing power plant site: They are operated in combination with the existing plants and, in doing so, allow a base-load power station to be used in the mid-merit and peak load range. The gas used does not replace the lignite, but complements it. As in the past, the lignite units are still operated continuously to generate base-load power. Using the waste heat of the two gas turbines in the lignite units G and H allows their electric capacity to be increased by 80 MW each. The steam that was previously extracted from the turbines of the lignite units to heat the feed water is now available for additional power generation. The investment volume of the two topping gas turbines totals €150 million.
